System of control for electric motors.



No.- 854,892. PATENTED MAY 28, 1907.

H. 1). JAMES. SYSTEM 01? 00mm. FOR ELECTRIC MOTORS.

APPLICATION FILED OCT. 3, 1905.

2 SHEETS-SHEET 1.

WITNESSES: INVENTOR @Zwm M 6.6% Q4 B Q 4 ATTORNEY No. 854,892. PATE-NTED MAY 28, 1907.

' H. D. JAMES.

SYSTEM OF CONTROL FOR ELECTRIC MOTORS.

APPLIOATIONIILED 0013, 1905.

Fig.2;

2 SHEETS-SHEET 2.

WITNESSES! 54 INVENTOR V ATTORNEY v UNITED srrns PATENT rricn.

HENRY D. JAMES, OF PITTSBURG PENNSYLVANIA, ASSIGNOR TO WESTING- HOUSE ELEOTRIO & MANUFACTURING COMPANY, A CORPORATION OF PENNSYLVANIA.

SYSTEM OF CONTROL FOR ELEGTFHC MOTORS.

Specifica ion of Letters Patent.

Patented May 28, 1907.

Application filed October 3,- 1906. Serial No. 281,188.

To all'whom it may concern Be it known that I, HENRY D. JAMES, a citizen of the United States, and a resident of Pittsburg, in the county of Allegheny and State of Pennsylvania, have invented a new and useful Improvement in Systems of Control for Electric Motors, of which the following is a specification.

My invention relates to systems of control for electric motors that are applied to the operation of elevators, machine tools and similar devices.

The object of my invention is to provide simple and efficient means for arranging the motor circuits for forward and reverse rotation, for preventingreversal of direction of rotation of the motor while the same generates an electromotive force exceeding a predetermined amount, and for arranging the motor circuits toeffect braking when the motor armature 1s disconnected from an external circuit.

Figure 1 of the accompanying drawings illustrates diagrammatically a system of controlembodying my invention and Fig. 2 illus- 'trates diagrammatically a system that embodies a modification of that shown in Fig. 1.

The system comprises as its principal elements a motor 1 having an armature 2 and shunt and series field magnet windings 3 and 4 respectively, a starting resistance 5,

switches 6, 7, 8 and 9 for removing the start- 7 ing resistance and the series field magnet winding from the circuit, a pair of switches 10 and 11 respectively for arranging the armature circuit ofthe motor for forward rotation, a pair of switches 12 and 13 for arranging the armature circuit. for reverse rotation, a braking resistance 14 that is connected in closed circuit with the armature 2 when. the motor is not supplied with energy, and a master switch 15 whereby operation of the aforesaid switches may be controlled. A non-inductive resistance 16 may be arranged in shunt to the shunt field magnet winding 3 of the motor and may be permanently adjusted to provide a suitable path for the inductive discharge of the field upon its disconnection from the supply circuit.

The upper terminals of the switches 6 to 9, inclusive, are connected to suitable points in the starting resistance 5 and the series field magnet winding 4, and the lower terminals are connected together and to a supply conductor 17. The switches 6, 7, 8 and 9 are provided with operating magnet windings 18, 19, 20 and 21, respectively, the circuit of the winding 18 being governed by the master switch 15, and the switches 6, 7 and 8 are provided with interlocking switches 22, 23 and 24, respectively, whereby the switches 7 8 and. 9 are prevented from operation except in a predetermined order. The operating magnet windings 19,20 and 21 are connected respectively between the upper terminals of the corresponding switches and terminals of the interlocking switches that are operated by the preceding switches, so that the switches 7, 8 and 9 may be closed only when the drops of potential over the portions of the circuit that are located between the switches have fallen below predetermined amounts. The arrangement of the circuits of this portion of the system is substantially like that shown and described in an application Serial 7 No. 253,632, filed by me April 3, 1905, and for that reason a more detailed description herein is deemed unnecessary. The switches 10 to 13, inclusive, whereby the circuits are arranged for either forward or reverse rotation, are provided, respec tively, with operating magnet w1nd1ngs25,

26, 27 and 28, the,circuits of the windingsl25 and 27 being governed primarily by the mast I switch 15. ."are ,a so provided with interlocking switches 29 and 30, respectively, which serve to pre- The switches 10 and 12 vent the switches 10.and 11 from operating simultaneously with the switches 12 and 13 and vice versa, and which also serve to prevent completion ofgthe circuits of the operating magnet windings 26 and 28 of the switches'll and 13, respectively, until the corresponding switch 10 or 12 is closed. The switches 10 and 12 are also provided with auxiliary switches 31 and 32, which, when both the switches 10 and 12 are open, connect the braking resistance 14 in closed cir-' cuit with the armature 2. The circuit which is thus established is from terminal 33 of the armature 2, throughcontact terminal 34 of the switch 10, the switch 31, resistance 14,

switch,32, contact terminal 35 of the switch 12, to terminal 36 of'the motor armature.

The switches 11 and 13 are provided respectively with interlockingswitches 1 and ico 38, which serve as additional means for preventing closure of the switches and '11 si multaneously with the switches 12 and 13 and vice versa, and also to maintain the circuit of the shunt field magnet Winding 3 while the electromotive force of the motor operating as a generator exceeds a redetermined amount, in a manner whic will be hereinafter more fully described.

The operation of the system is as follows: When switch lever 39 of .the master switch 15 is moved into engagement with conducting segment 40, a circuit is established from supply conductor 41, through switch lever 39, conducting segment 40, and shunt field magnet winding 3, to supply conductor 17. When the switch lever39 is moved into-engagement with corftact terminal 42, a circuit is established from supply conductor 41 through switch lever 39, contact terminal 42, operating magnet windin 25, interlocking switches and 38 inthen' lowermost positions, to supply conductor 17. Energ1zing 1 of the winding 25 closes the switch 10 and raises the interlocking switch 29 to its up ermost position, .a circuit being established by the latter switch from sup 1y conductor 41, through switch 10, inter ocking switch 29 and operating magnet winding 18, .to supply conductor17.- The. operating magnet winding18, bein energized, efie'cts closure of the switch 6. pon closure of the switch 6, an-

, other circuit is established from the supply conductor 41, through switch-10, interlocking switch 29, operating magnet winding 26 and. switch 6 to supply conductor17, the winding 26 being thereby-energized and the switch 11 closed. The armature circuit of the motor 1 is then established :firom .supply 18, 19, 20, 21 and 25will be interrupted and the corresponding switcheswill open. The

- switch 31 will then be closed and the arma- 5 .ture 2 connected, as before described, in

closed circuit with. the resistance 14. However, while the motor armature continues to rotate at an appreciable speed, the switch -1 1 will not open, since the-operating magnet winding 26 is energized from the motor 0 crating as agenerator and th'ecirouit of the shunt field magnet winding is thereby maintained closed. The circuit. which supplies energy to the operating magnet winding 26 is from terminal 33 of the armature 2, through supply conductor 17.

If the switch lever 39 contact terminal 44, conducting strip 45 of the interlocking switch 37, operating magnet winding '26., starting resistance 5;, series field magnet winding 4, and switch 1 1, to terminal 36 of the armature 2. armature 2 rotates at an appreciable speed, sufficient energy is supplied to the operating magnet winding 26 to maintain the switch 11 closed and the interlocking-switch 37 in its uppermost position. The circuit of the shunt field magnet winding which is main- As long as the motor.

tained is from the supply conductor 41, contactterminal 46, conducting strip 47, contact terminal 48 of the interlocking switch 37, and shunt field magnet winding 3, to the During the period that the motor operates as a generator, a dynamic brake is provided by the short-circuiting of the armature through the stopping resistance 14.

While the interlocking switch 37 is main- .tained in its uppermost position, operating magnet winding 27 of eswitch 12 may not be energized even though the switch lever 39 is moved into en agement with conducting segment 49 an contact terminal 50. Establishing of the motor circuits for reverse rotation of the motor is thereby prevented until the interlocking switch 37 again occupies itslowermost position; that is, until the counter electromotive force of the motor has fallen below a predetermined amount.

Operating magnet winding 25 .may, however, be again energized if the switch lever 39 is moved to the right for the purpose of causing rotation of the motor in the same direction as before the circuits were interrupted. The switches 12 .and 13 may be operated in a manner similar to that just described for the switches 10 and 11 if the switch lever 39 is moved to the left, and it is consequentlydeemed unnecessary to describe their operation more in detail. A mechanical brake 52 may also be provided for stoping the motor when it is disconnected fiom the external circuit, an op- .eratin magnet winding 53 for WhlCll is energize for .the. urpose of releasing the brake when the switc es 6 and 10 .are closed, the circuit thereby established being from the su ply conductor 41, through switch 10, intel lockin switch 29 in its uppermost position, bra e magnet winding 53 and switch 6, to en ply conductor 17 I It is fiequently desired to operate motors that are applied to machine tools and similar devices at different speeds in forwardand reverse directions of rotation, and my system, with but little modification, as shown in Fig. 2, provides such means.

1 W0 rheostats 54 and 55 that are adjusted respectively for forward and reverse rota- ICC .tion of the motor are connected in series sc ence line conductor 41 and the junction 56 of the rheostats is connected to contact terminals 57 and 58 respectively of interlocking switches 59 and 60, and the junction 61 of the rheostat 54 and the shunt field magnet winding 3 is connected to contact terminal 62 of the switch 60. The switch 9 is also provided with an interlocking switch 63,

the series field magnet winding 4 are removed from the circuit by the closing of the switch 9.

When the master switch lever 39 is moved into engagement with contact terminal 42 and the interlocking switch 59 is caused to occupy its uppermost position, the junction 56 of the rheostats '54 and 55 becomes connected with the supply conductor 41 by means of a circuit from the aforesaid junction, through contact terminal 57, conducting strip 66, and contact terminal 67, to the supply conductor 41. The rheostat 55 is thereby rendered ineffective, since both its terminals are connected to the same su ply conductor, and if the interlocking switch'63 is open, the circuit of the shunt field magnet winding is then from sup ly conductor 41,

through contact termina 67, conducting segment 66, contact terminal 57, rheostat 54 and shunt field magnet winding 3, to the supply conductor 17 4 If the master switch lever 39 is moved into engagement with contact terminals 50 and 51 and the switch is caused to occupy its uppermost position, a circuit is established in shunt to the rheostat 54 from the junction 56, through contact terminal 58, conducting seg ment 68, contact terminal .62, to the junction 61 of the rheostat 54 and shunt field magnet winding 3, the rheostat 54 being thereby rendered inefiective. If the interlocking switch 63 is open, the circuit of the shunt field magnet winding is then from supply conductor 41, through rheostat 55, contact terminal 58, conducting segment 68,- contact terminal 62 and the shunt field magnet winding 3, to the supply conductor 17 Thus it is seen that in the system of Fig. 2

' the interlocking switches 59 and 60 serve to connect the rheostat in circuit with the shunt field magnet winding which is adjusted for the corresponding direction of rotation.

It will be observed that in this latter system the segments 40 and 49 of the master snitch 15 are omitted and the shunt field magnet winding is connected directly in circuit between the supply conductors 17 and 41. It is therefore effective for either forward or reverse rotation 'or for braking purposes.

It should also be noted that contact terminals 69 and 70 respectively of interlocking switches 59 and 71 are connected directly to supply conductor 41, whereas in the system of Fig. 1 corresponding contact terminals 44 and 72 are connected to terminal 34 of switch 10 by means of which it may be connected to the supply conductor 41. The connections for the interlocking switches that are operated. by the other pair of reversing switches are in each case similar to those just described. In Fig. 2 the circuits are arranged as stated in order to prevent opening of the switches 11 and 13, if for any reason, such as imperfect operation, one or more of the switches 6 to 9, inclusive, remain closed after the circuits of their operating magnet windings have been interrupted. The operation of this portion of the system will be readily understood by tracingthe circuit from supplyconductor 41, through interlocking switch 59 in its uppermost" position by way of contact terminal 69, operating magnet winding 26, more or less of the field magnet winding 4 and the resistance 5 and one or the other of the switches 6 to 9, inclusive, to supply conductor 17.

While the switches are represented as being operated electro-magnetically, it will be readily understood that they may be operated by any other suitable means, suchas fluid-pressure, and that the operating magnet windings may serve only to control the operation of the switches, such as by governing the operation of the valves in the pneumatic circuits. The specific structural details of the devices shown form no part of the present invention and may comprise any of the suitable devices which have heretofore been provided or which may be invented in the future.

I do not intend to limit my invention to the specific arrangement of circuits, but desire to cover broadly means having substantially the same mode of operation for effecting the functions ascribed to the system.

I claim as my invention:

1. The combination withan electric motor, of two pairs of switches for connecting the motor armature respectively for forward and reverse rotation, the operation of the second switch of each pair being governed by that of the first, and means for preventing simultaneous closure of switches belonging to difierent pairs.

2. The combination with an electric motor, of two pairs of switches for. connecting the motor armaturerespectively for forward and reverse rotation, the operaion of the second switch of each pair being governed by that'of the first.

3. The combination with an electric motor, of two pairs of switches for connecting and reverse rotation and means for preventing closure of the second switch of each pair until after closure of the first.

4. The combination with an electric motor, of two pairs of switches for connecting the motor armature respectively for forward and reverse rotation, means for reventin closure of the second switch of eac pair unti after closure of the first and manually operated means for controlling operation of the first switch of each pair.

5. The combination with an electric mo- :tor, of two pairs of switches for connecting the motor armature respectively for forward and reverse rotation,.of means for preventing closure of the second switch of each air until after closure of the first and means for controlling operation of the first switch of each pair.

6. The combination with an electric motor, of two pairs of switches for connecting the motor armature respectively for forward and reverse rotation and means for prevent- ,tor, of two pairs of switches for connectin the motor armature respectively for forwar and-reverse rotation, the closing of the second switch of each air being governed by the operation of the st; and means for preventing opem'n of the second switch of each pair while the e ectromotive force of the motor operating as a generator exceeds a predetermmed amount.

9. The combination withan electric motor, of two pairs of switches for connectin the motor armature respectively for forward and reverse rotation, means for controlling operation of the first switch of each pair, means for preventing closure of the second switch of eachflpair until after closure'of the first and means for preventin opening of the second switch of each pair w la the electromotive force of the motor operating as a generator exceeds 'a predetermined amount.

' V 10. The combination with an electric motor, of two pairs of switches for connectin the motor armature respectively for forwar and. reverse rotation, a resistance, and means for connecting the same in closed circuit with the motor armature when one switch of each pair iso en.

1 1. T 1e combination with amotor having an armatureand a field magnet winding, of

circuit 0 two pairs of separately actuated switches for connecting the motor armature respectively for forward and reverse rotation and means for maintainin the circuit of the field magnet winding w .ile the speed of the motor exceeds a predetermined amount.

12. The combination with a motor'having an armature and a field magnet winding, of

reverse rotation and means governed by said switchesand dependent in operation u on the electromotive force of the motor w en operatin as a generator for maintaining the g the field magnet winding while the said electromotive force exceeds a predetermined amount.

13. The combination with a motor. having an armature and a field magnet winding, of two pairs of switches for connecting the mo 'two pairs of switches for connecting the motor armature respectively for forward and tor armature respectively for forward and reverse rotation and means controlled by one switch of each pair for maintaining the circuit of the field magnet winding while the electromo tive force of the motor operating as a generator exceeds a predetermined amount.

14. The combination with a motor having an armature and a field magnet winding, of two pairs of switches for connecting the motor armature respectively forforward and reverse rotation, means for controlling operation of the first switch of each pair, means for preventing closure of the second switch of each pair until after closure of the first and means controlled by the second switch of each pair for maintaining the circuit of thr.

field magnet winding while the electromotive force of the motor-operating as a generator exceeds a predetermined amount.

15. The combination with a motor having an armature and a field magnet winding, of two pairs of switches for connecting the motor armature respectively for forward and reverse rotation, means for controlling operation'of the first switch of each pair, means for preventing operation of the first switch. i of each pair when a non-corresponding sec- 'ond switch is closed, means for mamtammg the circuit of the field magnet winding while the s eed of the motor exceeds a redetermine connecting the same in closed circuit with the motor armature when the first switches of both pairs are open.

16. The combination with a motor having an armature and a field magnetwinding, of

two pairs of switches for connecting the motor armature respectively for forward and reverse rotation, a master switch whereby the circuit of the field magnet winding is established and then the first switch of one of the pairs caused to close, the operation of the second. switch of each pair being governed by that of the first.

amount, a resistance,.and means for 17. The combination with a motor having an armature and a field magnet winding, and resistances located in the circuit of the field magnet winding that are adjusted respec tively for forward and reverse rotation of the motor, of two pairs of switches for connecting the motor armature respectively for forward and reverse rotation and means controlled by one of the switches of each pair for removing the resistance from the field magnet circuit which does not correspond with the direction of rotation of the motor.

18. The combination with a motor having an armature and a field magnet winding, and resistances located in the circuit of the field magnet winding that are adjusted respectively for forward and reverse rotation of the motor, of two pairs bf switches for connecting the motor armature respectively for forward and reverse rotation, means for controlling the operation of the first switch of each pair, means for preventing closure of the second switch of each pair until after closure of the first, and means controlled by the second switch of each pair for removing the non-corresponding resistance from the circuit of the field magnet winding.

19. The combination with a motor having an armature and a field magnet Winding, of two separate resistances in circuit with the field magnet winding that are adjusted respectively for forward and reverse rotation of the motor, means for further controlling the motor circuits and means for removing the resistances from the circuit of the field magnet winding until after completion of operation of the aforesaid means.

20. The combination with a motor having an armature and shunt and series field magnet windings, two separate resistances in circuit with the shunt field magnet winding that are adjusted res ectively for forward and reverse rotation 0 the motor and aresistance in the armature circuit, of means for removing the resistance and series field magnet Winding from the armature circuit and means for removing the resistances from the circuit of the shunt field magnet winding until after completion of operation of the aforesaid means;

21. The combination with an. electric motor, of two pairs of switches for connecting the motor armature respectively for forward and. reverse rotation, controlling magnet windings for the switches and means for preventing energizing of the controlling magnet windin ofone of the switches of each pair until after closure of the other switch.

22. The combination with an electric motor, of two pairs of switches for connecting the motor armature respectively for forward and reverse rotation, controlling magnet windings therefor and auxiliary switches operated thereby which prevent closure of one of the switches of each pair until after closure of the other switch.

23. The combination with an electric motor, of two pairs of switches for connecting the motor armature respectively for forward and reverse rotation, controlling magnet windings therefor and auxiliary switches that are ofperated by one of the switches of each pair or preventing closure of the correspond ing other switches until after operation thereof and for preventing simultaneous operation of the switches belonging'to different pairs.

24. The combination with an electric motor, of two pairs of switches for connecting the motor armature respectively for forward and reverse rotation, controlling magnet windings therefor and auxiliary switches operated thereby for preventing closure of one of the switches of each pair until. after closure of the other.

25. Thecombination with an electric motor, of two pairs of switches for connecting the motor armature respectively for forward and reverse rotation, controlling magnet windings therefor and auxiliary switches operated thereby for preventing closure of one of the switches of each pair until after closure of the other and for preventing opening of the second switch of each pair while the electro motive force of the motor operating as a generator exceeds a predetermined amount.

26. The combination with an electricnno-- tor, of two pairs of switches for connecting the motor armature respectively for forward and reverse rotation, controlling magnet windings therefor and auxiliary switches operated thereby for preventing energizing of the controlling magnet winding of one switch of each pair untiltafter operation of the other switch and for preventing opening of the second switch of each pair while the electromotive force of the motor operating as a gen erator exceeds a predetermined amount.

27. The combination with an electric motor having an armature and field magnet of the switches of each pair until after closure of the other switch for preventing opening of the second switch and for maintaining the circuit of the field magnet winding while the electromotive force of the motor operating as a'generator exceeds a predetermined 30. The combination with a .motor having an armature and a field magnetwinding and resistances located in the circuit of the field magnet winding that are adjusted respectively for forward and reverse rotation of the motor, of two pairs of switches for con necting the motor armature respectively for forward and reverse rotation and auxiliary switches operated thereby for removing that resistance from the field circuit which is not adaptedto the desired. direction :of rotation of-the motor.

field magnet "winding that-are adjusted re spectively for forward and reverse rotation of the motor, meansfor further controlling themotor circuits and means for removin V predetermined speed.

- an armature and shunt and series field magnet windings, resistances in circuit with the.

switches for shuntingthe resistances in the circuit of the shunt field ,magnet winding shunt fieldmagnet winding that are adjusted res ectively for forward and reverse rotation of t e motor and a're'sistance in the armature circuit,- of switches for removing the resistance and the series field magnet winding from-the armature circuit, and an interlocking switch operated bygone of the aforesaid until the motor attains a predetermined speed.

- 33. The combination with a motor having: anarmature and a field magnet winding, of' two separate resistances in circuit with the field magnet winding that are adjusted're- 'spective'ly for forward and reverse rotation of the motor, a set of switches "for controlling the motor circuits and interlocking switches perated 'byswitches of said set for removing at resistance from the field circuit whichis not adapted to the desired direction of rotation of the motor.

34, The combination tor, of two pairs of switches for connecting a each pair remains o the resistances from the circuit of the fiel magnet winding until the motor attains a tor, of two pairs of switches for connecting the motor armature respectively for forwar 1 26 with :an electric mofurther controlling the motor circuits, and means for preventing. o ening of the second switch 'ofeach pair whi e one or more of the said set of switches remains closed.

35.: .The combination with anelectric mo" tor, of two pairs of switches for connectin the motor armature respectively for forwarr, and reverse rotation, means for preventing closure of the second switch of each air until ,afte-r closure of the first, a set of switches for 7 5 further controlling the motor circuits and meansfor preventing o ening of the second switch of each pair whi e one or more of the set of switches remains closed.

36. The combination with an electric mo tor, of two pairs of switches for connecting the motor armature respectively for forward and reverse rotation, a brake a-nd means that are dependent in -o oration upon the filst. switchv of each air fllr controlling the same. 8 5

v 37. The com ination with an electricmo tor, of two pairs of switches'for connecting the motor armature respectively for forward and reverse rotation, a brake magnet winch switch of each pair for controlling the circuit 31. The combination witha motor having 3 i an armature and a field magnet winding, of two separate resistances in circuit with the thereof. .I v 38. The combination with anelectric'motor, of'two pairs of switches for connecting the motor armature-res ectively for forward and reverse rotation, a brake and means for releasing the same while the first switch of:

n. 39. The 'combinali n with an electric motor, of two pairs of separately actuated ioo 'swi'tchesfor connecting the motor armature 32. The combination with a motor having after closure of the first switch-of one of said .pa irs; I I a 40. The combination with-an electric mm tor, of two pairsof switches for connect-1n the motor armature respectively for forwarr I 10 and reverse rotation, a set of switches for f-urther controlling the motor circuits, means for. preventing closure of the first switch of said set until after closure oft-he first switch of one of said pairs and means for preventing 1 r5 closure of the second switch of each pair un.

til after closureof the first switch of'saidset, 41. The combination'with an electric moand reverse rotation, a stof swltches for further controlling the motorci rcuits, a brake,

.means for preventing closure 'of the first switch of said set-until after closure of the first switch'of one of saidpairs and means for 1 2 5 preventing closure of the second switch of each of said pairs and release of the brake un til after closure of the first switch of said set.

142. The combination with an electric motor, of two pairs of switches for connecting 1 o masses the motor armature respectively for forward and reverse rotation a set of switches for further controlling the motor circuits, a brake, interlocking switches operated respectively by the first switch of each pair for preventing closure of the first switch of said set until after closure of the first switch of one of said pairs and means for preventing closure of the second switch of said pairs and release of the brake until after closure of the first switch of said set.

43. The combination with an electric motor, of two pairs of switches for connecting the motor armature respectively for forward and reverse rotation, a set of switches for further controlling the motor circuits and interlocking switches operated respectively by the first switches of said airs for preventing closure of the first swltc of said set until operation of the corresponding main switches.

In testimony whereof, I have hereunto subscribed my name this 30th day of September, 1905.

HENRY D. JAMES.

Witnesses:

IDA W. REINEoKE, BIRNEY HINES. 

